The invention relates to a microvalve comprising a drive housing in which a magnetic drive is arranged that includes at least one solenoid and an armature adapted to be actuated by the solenoid, a flanged housing which is mounted against the drive housing and in which at least one valve seat is formed, and a diaphragm arranged between the drive housing and the flanged housing, which diaphragm is adapted to be pressed against the valve seat by means of a commutation rocker coupled to the armature.
In a microvalve, any manufacturing tolerances have a more aggravating effect the more compact the valves are by design, because the actuation forces that are obtainable by the drive of the valve, preferably a solenoid, are greatly reduced with an increasingly smaller constructional volume, whereas the manufacturing tolerances of the components increase in relative terms.
The invention provides an extremely compact microvalve in which tolerances are avoided in particular at the interface between drive and commutation rocker, in order to achieve a further miniaturization with as unchanged technical specifications and low production costs as possible.
According to the invention, the commutation rocker has a pivot bearing, the axis of which assumes a position which is determined by direct abutment on a seating surface of the flanged housing facing the drive housing. Thus, the component and manufacturing tolerances are eliminated, which would be inevitable in case the commutation rocker is supported in or on the drive housing.
In advantageous further developments of the invention, in spite of a reduced constructional volume of the microvalve, the commutation forces that can be obtained are increased owing to an optimum utilization of space and a deliberate arrangement of solenoids and iron yoke; hence, the performance data of the next larger valve type are achieved or even excelled.
In addition, in the preferred embodiment of the microvalve the space that is in contact with the medium is hermetically separated from the drive part by the diaphragm, whereby due to the flexing resistance showing an effect during the actuation of the diaphragm there is an additional increase in actuation forces that are required.
In a first design of the microvalve the armature is not mounted in the drive housing, as with known designs, but is pivotally mounted directly on or in the solenoid, whereby the friction counteracting its pivoting motion is reduced.
In a second design of the microvalve the armature is formed in one piece with the commutation rocker and thereby is supported together with the rocker on the seating surface of the flanged housing, whereby further component and manufacturing tolerances as well as friction between armature and commutation rocker are avoided.